In the related art, for example, an apparatus disclosed, in JP 2009-84829A (Reference 1), is known as an antenna drive apparatus. The antenna drive apparatus is configured to activate four switching elements constituting a full-bridge circuit (H-bridge circuit) by a drive circuit of a drive control unit (drive ECU) to perform a switching operation to generate an AC signal of a predetermined frequency and supply a resonant frequency corresponding to the above-described frequency to an antenna. There is proposed to equalize impedance values at two analogue circuit portions disposed with respect to both electric wires of a wire harness electrically connecting the drive control unit and the antenna for suppressing a leak or the like of an electromagnetic wave from the wire harness.
In JP 2009-84829A (Reference 1), there is no description about driving of members other than the antenna by the drive control unit. However, it is desired to also drive a sensing member by the drive control unit for sensing approach or contact of a person.
In other words, as illustrated in FIG. 7, a sensing member 92 is mounted on a driven control unit 90 on which an antenna 91 is mounted. Then, a drive ECU 95 as the drive control unit and the driven control unit 90 are electrically connected by a pair of electric wires W91 and W92 for supplying an AC signal to the antenna 91. The drive ECU 95 and the driven control unit 90 are also electrically connected by a pair of electric wires W93 and W94 for supplying a DC signal to the sensing member 92. Furthermore, the drive ECU 95 and the driven control unit 90 are electrically connected by a pair of electric wires W95 and W96 for outputting a sensing signal (here, a lock sensing signal and an unlock sensing signal) indicating sensing of approach or contact of a person to the drive ECU 95.
In this case, six electric wires W91 to W96 connecting the drive ECU 95 and the driven control unit 90 are required and hence increase in size and weight as an entire apparatus is inevitable.
In JP 2007-162246A (Reference 2), a drive control unit (vehicle-mounted controller) and an antenna and a sensing member (touch sensor) are electrically connected via a common electric wire (connecting line) and setting resonant frequencies of the antenna and the sensing member to be values different from each other, whereby the antenna or the sensing member may be selectively driven. However, in JP 2007-162246A (Reference 2), even though the method of sensing the approach or contact of a person in association with driving of the sensing member is indicated, an electrical configuration for outputting a sensing signal which indicates the fact that the approach or the contact has been sensed to the drive control unit is not described. In other words, it is estimated that an electric wire for outputting the sensing signal of the sensing member to the drive control unit is additionally required.
Therefore, providing two electric wires (connecting lines) for connecting the drive ECU 95 and the driven control unit 90 and using these two electric wires commonly for power supply to the antenna 91 and power supply to and output from the sensing signal of the sensing member 92 are reviewed. However, when the sensing signal is output when the antenna 91 is being driven, for example, there is a probability of erroneous sensing at the drive ECU 95 due to an AC signal superimposed with the sensing signal. In addition, if the sensing performance of the sensing member 92 itself is deteriorated under the influence of an electromagnetic field when driving the antenna 91, reliability of the sensing signal is lowered accordingly.
A need thus exists for an antenna drive apparatus capable of reducing the number of connecting lines with respect to a drive control unit without impairing reliability of a sensing member configured to sense approach or contact of a person.